This invention relates generally to a fluid activated percussive impact tool having a piston reciprocal in a housing of such tool, and more particularly to a lubrication system for a jackhammer in which the piston is longitudinally reciprocal and the drill steel is rotated as well as impacted by the piston.
Typical lubrication systems on handheld jackhammers and paving breakers incorporate an oil reserve chamber and some type of metering device. The reserve chamber is generally connected to the high pressure air supply. High pressure air enters the chamber until the chamber reaches the pressure of the supply. Once the supply pressure is relieved, any oil that may be in the chamber will meter back into the high pressure supply line. Once the high pressure chamber is re-pressurized, any oil in the line is then carried into the tool to help lubricate the running components. The metering device to prevent large quantities of oil from escaping the oil reserve can be a complex metering device or a simple sintered, porous filter element. Even with the oil being metered, the oil volume entering the tool is often more that the tool requires for proper operation.
The foregoing illustrates limitations known to exist in present jackhammers. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.